I. Field of the Invention
The present invention relates to an image processing apparatus and, more particularly, to an apparatus for converting an image of interest into an image signal.
II. Description of the Related Art
Most of the conventional copying machines have employed a system exemplified by an electrophotographic copying machine for directly projecting an optical image obtained by optically reading an original onto a photosensitive body and developing a latent image corresponding to the optical image to form a visual image.
In recent years, a copying machine has been proposed wherein information obtained with reading an original by an image reader unit is converted into an electrical signal, the electrical signal is sent to an image output unit, and an image is formed on a recording medium on the basis of image information sent to the image output unit.
The copying machine described above can be arranged by connecting the image reader unit (to be referred to as a scanner hereinafter) and the image output unit (to be referred to as a printer hereinafter) via signal lines. Therefore, even if the scanner and the printer are located at remote positions, the copying machine can be properly operated. In addition, this copying machine has advantages in that image processing such as trimming, synthesis, and variable magnification of the image can be arbitrarily performed as compared with the conventional copying machine since the image information of the original is converted into the electrical signal.
In particular, a color copying machine proposes various advanced functions associated with color information, such as color conversion.
There is also known a copying machine comprising a one-dimensional image sensor for reading images of a plurality of pixels in a first direction and a recording head for recording the images of the plurality of pixels in the first direction on the basis of image data provided from the image sensor, wherein a read position of the image sensor and a recording position of the recording head are moved in a main scanning direction perpendicular to the first direction, and the read position of the image sensor and the recording position of the recording head are moved in a sub scanning direction parallel to the first direction, thereby copying a large-sized original image.
In the conventional copying machine and the conventional original reading apparatus of this type, various types of coordinate designation mechanisms have been proposed to designate positions on an original so as to perform area processing such as trimming.
However, since a coordinate designation mechanism and an original reading mechanism are different from each other, coordinate designation is performed and then an original is placed on the reading mechanism. Therefore, it is very difficult to accurately position the original on the reading mechanism with respect to coordinate designation. In view of this, another function for detecting the position of the original is also required.
In the conventional copying machines and the conventional image reading apparatuses, various types of apparatuses or mechanisms for designating an original size have been proposed. Information of the size of an original placed on an original table is obtained by one scanning cycle of the original. However, the following disadvantages are presented:
(1) A scanning operation for measuring only an original size is required and results in inefficiency.
(2) Accurate original size information cannot be obtained depending on the quality of an original.
(3) A means for determining an original size is required.
An apparatus capable of processing a color image has functions for adjusting color balance of an original and changing a hue of an original.
In this apparatus, however, if information of a color subjected to color conversion cannot be accurately detected during conversion such as color conversion by utilizing the above functions, these functions cannot be effectively utilized.
For example, when a color to be converted is blue, blue cannot be quantitatively designated.